Contact supporting means for electromagnetic switches



July-28, 1959 H. E. scHLl-:ICHER 2,397,311

CONTACT SUPPORTING MEANS FOR ELECTROMAGNETIC SWITCHES Filed June 14. 1956 Haro/d ESch/e/c/ver BY h/s affomeys United States Patent Of CONTACT SUPPORTING MEANS FOR ELECTRO- MAGNETIC SWITCHES Harold E. Schleicher, West Hartford, Conn., assignor to The Arrow-Hart & Hegeman Electric Company, Hartford, Conn., a corporation of Connecticut yApplication June 14, 1956, Serial No. I591,413

13 Claims. (Cl. 200-87) This invention relates to electromagnetic switches and more particularly to contact supporting means for such switches which are readily accessible for replacement or for changing the relative positions of the fixed and movable contact members.

Electromagnetic switches are in constant use in great volume and are frequently required to operate many times in the course of the day or even in the course of an hour. The circuits to be controlled vary considerably in different usages of the switch. Moeover, it is sometimes necessary to change an established circuit arrangement so that a normally-open set of contacts will be normally closed and vice versa. Such demands require exibility not only in use of the switch, but also in the course of assembly because the switch manufacturer must supply switches for varied usages as specified by his customers.

Therefore, it is an object of this invention to provide an arrangement of both fixed and movable contacts which will permit alternation of the relationship from normally-closed to normally-open and vice versa by simple interchange of the movable contact in its mounting without the need for any tools or any reconstruction or any alteration in form in the switch parts, but merely by use of ones lingers to rearrange the parts provided.

Since some of the contacts may be normally-closed and some may be normally-open, it is desirable to have them all disengaged at the time any change or reversal of the contacts is to be done. Therefore, it is an object of the invention to provide means which is inoperative during normal operation of the switch but which may be manually activated to hold the movable contacts in a neutral position wherein neither normally-engaged nor normallydisengaged contacts are engaged, thus facilitating manipulation of the movable contact.

It is often necessary also to be able to add sets of contacts where additional poles are to be provided in the switch. Therefore, it is an object of the invention to provide for removal and replacement, readily, of the movable contact supporting means and of the xed and movable contacts.

Other objects and advantages of the invention will become apparent as the invention is described in connection with the accompanying drawing.

section, showing the neutral positioning means.

2,897,311 Patented July 28, 1959 Referring to the drawing, the whole switch structure is mounted upon and supported from a main backplate 10 of heavy sheet metal. Pairs of fixed switch contacts 12 and 14, preferably stamped into L-shape, are secured by screw bolts or otherwise to cooperating molded insulating blocks 16 and 18 which are in turn secured to a switch supporting plate 20. The switch supporting plate 20 is mounted upon the backplate 10 and is preferably stamped from sheet metal. The fixed contacts 12 and 14 are provided with contact buttons 12a and 14a on one surface of the shorter leg; and similar contact buttons 12e and 14e are mounted on the opposite side of said leg, facing in the opposite direction from the buttons 12a and 14a. It will be understood that a pair of fixed contact members 12 and 14 are provided for each pole of the switch and will be located in adjoining, facing and cooperating recesses molded in the blocks 16 and 18. The pairs of contact buttons 12C and 14e are adapted to be engaged by contact buttons 30b facing in the same direction and mounted upon the ends of a bridging contact member 30 which is preferably stamped in strip form from sheet metal.

In order that the bridging contact may be normally disengaged when the switch is deenergized from the contact buttons 12e and 14e or may be nomlally engaged with the contacts 12a and 14a, the bridging contact member 30 is mountable alternately and interchangeably in either of two positions in a cage member, designated by the numeral 40. The cage 40 may conveniently be stamped from sheet metal and bent into U-shape having substantially the form illustrated in Figure 4. The parallel sides 41, 42 of the cage may have their free ends joined lby a stamped sheet metal mounting bracket 44 of U-shape with its transverse portion 44t extending between the sides 41 and 42 and having extending lugs 44a extending into slots in the sides 41 and 42 and may be peened over so that the cage 40 and its supporting 'bracket 44 will comprise a unitary structure. The parallel A46 engages at one end with the transverse portion 44t of the supporting bracket 44. Its other end engages a slidable supporting member or saddle 45 which may be stamped from thin sheet metal into the form shown in Fig. 4a. The saddle has oppositely directed arms 47 extending beyond the parallel edges of the sides 41 and 42 of the cage 40. These arms are preferably bent at oblique angles in the same direction from the central portion, for easier grasping by ones lingers when it is desired to insert, remove, replace or reverse the bridging contact member 30. When these arms 47 are grasped between the thumb and foreiinger, the saddle member can be slid against the pressure of the spring 46 leaving adequate room for insertion or removal of the bridging contact 30 laterally into or from the cage 40. When the saddle member is released, the spring 46 presses it against the middle of the bridging contact.

Parallel sides 48 on the saddle are bent up in the same direction and slide along the cage sides 41, 42. The saddle sides, together with laterally extending lugs 49 entering lengthwise openings in the cage sides, guide the movement of the saddle in the cage.

The movement of the bridging contact under the pressure of the saddle and spring 46 is limited by stops 41s, 42s lwhich are formed by thin narrow transverse strips lanced inwardly from each of the sides 41 and 42.

When the contact 30 is removed, the movement of thesaddle mem'ber 45 is likewise limited by the stops 41s, 42s.

The spring 46 at the opposite end of the cage seats upon and presses at one end against an identical saddle 45 and at its other end presses against the transverse portion 43 of the cage.

To center and maintain the coil spring 46', a circular hole is punched in the transverse portion and the metal around it is extruded inwardly as at 43. A similar aperture and extrusion may be provided for a similar purpose inthe transverse portion 44t of the supporting bracket 44 of Figure 4.

' The contact member 30 is positionable interchangeably. It may be placed as illustrated in Figures 2 and 4 or in a reversed position as in Figure 3.

In Figures 2 and 4 the contact 30 is held between saddle 45 and stops 41s, 42s with the contact buttons -facing'the fixed contact buttons 12C, 14C. To reverse the contact 30 fora closed-switch condition when deenergized, the saddle 45 is grasped and pushed against the spring 46 until the contact 30 can be slid out laterally from the cage 40. The contact 30 is then turned over and inserted between the saddle 45 and the stops 41s, 42s, with the buttons facing oppositely, i.e., towardy contacts 12a, 14a. For the insertion of contact 30, the saddle 45' is pushed against the spring 46' to provide room for its insertion as in the case of saddle 45. The whole operation is easily accomplished without tools, without change of form of any part and merely by linger-tip manual operations.

In this new and reversed position of the bridging contact member, the buttons 30b engage the buttons 12a and 14a as illustrated in Figure 3, when the movable contact carrier is in the deenergized position of the switch in contrast to the separation of the movable contact from the buttons 12al and 14c when the bridging contact is mounted as illustrated in Figures 2 and 4.

Preferably, the bridging contact member has its end portions oiset in the same direction from the midportion as illustrated in order to provide for greater movement with a shorter cage than would be necessary if the bridging contact were straight.

The insulating block 50 which carries the movable contact assemblies is supported upon the shorter leg 54a of a Z-shaped metal carriage by-screw bolts 53 which may be readily unscrewed to remove the whole movable contact assembly comprising the supporting block 50 and all of the cages 4() and bridging contacts 30 carried thereby. The other or longer leg 54b of the carriage is slidable parallel to and spaced slightly above the surface of the switch supporting plate.

On one end of the carriage a T-shaped electromagnetic armature 60 is mounted, the leg 62 thereof being slidable within a conventional solenoid coil 64 which is mounted upon the middle leg 72 of an E-shaped electromagnet field piece designated generally by the numeral 70. The eld piece is xedly mounted. upon the switch supporting plate by screw bolts 71 in conventional fashion. A transverse pin 63 passes through the midpoint of the head portion of the armature 60 and affords a pivotal and slidable mounting for the armature 60 in parallel slots 66 formed in the ends of parallel legs of a U-shaped supporting bracket and designated generally by the numeral 68. The bracket 68 is secured to and mounted upon the switch supporting plate 20. The pin 63 also passes through parallel arms 54C, 54d which are bent up from the longer leg 54b of the movable contact carriage, away from the switch supporting plate 20 near the end of the long leg 54h.

The movable contact carriage is pivotally supported at the `other end by a strut 58 having a knife edge at one end engaging the under surface of the short leg 54a of the carriage while its opposite edge engages the switch supporting plate 20, preferably by two short linger extensions or bifurcations from said other end of the strut and entering small slots or apertures punched in the plate t positions.

20 and of suicient size toallow free pivotal movement of the strut as the contact carriage is moved by the electromagnet armature. Thus, the end of the Contact carrier nearest the contacts is pivotally supported in a substantially frictionless manner by the strut 58 while the opposite end of the contact carrier is supported slidably in the slots 66 by the pin 64. The carrier can thus move with a minimum amount of friction. Rectilinear movement of the carriage is also insured by a guide stud69 mounted in the switch supporting plate 20 and extending through the longer carriage leg 54h which has a guide slot to receive the stud.

To hold the carriage in engagement with the upper end of the strut 58, coiled tension springs 55 each have one end looped in an aperture formed in the movable contact carrier inwardly of the short leg 54a while the other end of each spring is looped through an anchoring loop 57 and lanced out of the switch supporting plate 20. The anchoring loop A57 is of such length as to permit the end of the spring to be located in one or another of a'plurality of For that purpose the inner surface of the loop is serrated. By locating the springs in one or another of the positions determined by serrations, the spring tension may =be adjusted to suit the contacting conditions. The springs not only hold the movable contact carrier in engagement with the strut 58, but also exert suilicient tension to move the movable contact carrier to deenergized position of the electromagnet as illustrated in Figure 2.

Thus, it may be seen that as the armaturek 60 is attracted, its Iforce is transmitted through the pin 64 to the carriage arms 54e, 54d whereby the carriage is moved causing the bridging contacts to move from the position of Figure 2 to cause engagement of the movable-contact buttons 30h with the xed contact buttons 12a` and 14C. Upon such engagement, the carrier can continue to move while the spring 46 is further compressed and maintains the bridging contact rmly engaged with the fixed contacts.

In order to facilitate the reversing of the bridging contacts from the position of Figure 2 to the position of Figure 3 without disassembling the insulating bar 50 and the lparts it carries from the carriage, the upper insulating block 18 which carries the xed contact members 1,2 may be removed by unscrewing the nuts from bolts 19 by which the insulating block 18 and its associated insulating block 16 are held against the switch supporting plate 20. Uponremoval of these nuts, the block 18 may be lifted olf together with the xed contacts 12, leaving the movable contact structure clearly available and open to access for reversing or interchanging or replacing the movable contacts. Preferably, the electromagnetic switch structure will have been previously disassociated or unplugged from the terminal structure (as hereinafter mentioned).

Since the bridging contacts of some of the poles may desirably be normally engaged, i.e. engaged in the deenergized position of the switch as illustrated in Figure 3, while other bridging contacts may desirably be normally disengaged as illustrated in Figure 2, it is desirable when the contacts are to be shifted or interchanged or rearranged to have them and their carrier positionable in a neutral position in which no movable contact engages any fixed contact. In order to locate the contacts and movable contact carrier in such Aa neutral position, a flexible leaf spring member is riveted to the lower surface of the long leg 5 4b of the carriage and extends longitudinally beyond the leg. In normal operation of the switch, the leaf spring member 80 is adapted to slide over and above a stop member 82 located-midway between the sides of the switch supporting plate 20 at the end thereof. Such member vmay comprise a stud with an enlarged head tapering toward the supporting plate 20 and secured fixedly in position onsad plate 20. While the switch is held in energized position, the leaf spring member 80 may be depressed from dotted position illustrated in Figure 5 to the full line position of that figure, so that when the contact carriage moves toward deenergized position the end of the leaf spring member 80 will engage beneath the enlarged head of the stop 82. Such engagement of the end of the spring will prevent further movement of the contact carrier to fully deenergized or unattracted position and will thus hold the carrier and bridging contacts in a neutral position wherein they do not engage any xed contacts, whether the contacts be set for normal engagement or normal disengagement.

After the change or rearrangement has been made of the movable contacts, the next energizing movement of the switch will permit the leaf spring member 80, under its own resiliency, to move from under the head of the stop member 82 into the plane illustrated in dotted lines, Figure 5. Hence, upon the next deenergization of the switch, the leaf spring positioning member will automatically be ineffective and inoperative.

The contact structure as above described is applicable to electromagnetic switch structures of various sorts besides the specific embodiment in connection with which the invention has been disclosed herein.

In the present invention, the fixed and movable parts of the electromagnetic structure are removable forwardly of the switch mounting plate 20. By pivotal movement about the pin 63 upon removal of the securing bolts 71, the armature and field piece can be swung forward as is more fully described in my copending application, Serial No. 591,414, filed June 14, 1956, now Patent No. 2,859,302.

Also in the present embodiment, the electromagnet operating structure together with the xed and movable contact structure may be unplugged and removed bodily as a unit from the terminal structure by sliding movement of the switch supporting plate 20 over the backplate away from the terminal structure, as is more fully described and claimed in said copending application..

Many modications within the scopev of the invention will occur to those skilled in the art. Therefore, I do not limit the invention to the specific embodiment illustrated and described.

What is claimed is:

1. In an electric switch, a pair of separate fixed contact members each having oppositely facing contact surfaces on opposite sides thereof, a bridging contact member having contact surfaces engageable with and disengageable from one or the other of similarly facing pairs of said fixed contact surfaces, a cage affording a mounting for said bridging contact, a carrier movable between two positions on which said cage is secured, means on said cage for interchangeably mounting said bridging contact in spaced positions in the cage, while said cage remains secured -on said carrier, with its contact surfaces facing one of said pairs of fixed contact surfaces when in one position and facing the opposite of said xed contact surfaces when in the other position in said cage, and means in said cage to bias said bridging contact member toward said fixed contact members in each of the alternate positions of said bridging contact.

2. Contact structure for an electric switch as claimed in claim l wherein the cage comprises parallel side portions between said bridging contact member is mountable by endwise insertion and said biasing means includes a spring, and spring seating and positioning means against which the ends of said spring press preventing lateral movement of said ends.

3. Contact structure for an electric switch as claimed in claim 2 wherein the cage has stop means extending between s aid parallel sides limiting the movement of the contact member.

4. Contact structure for an electric switch as claimed in claim 1 wherein the cage comprises parallel side portions between said bridging contact member is mountable .by endwise insertion, and stop means extending between 6 said parallel sides limiting the movement of the contact member.

5. Contact structure for an electric switch as claimed in claim l wherein the cage comprises parallel side portions between which said bridging contact member is mountable by endwise insertion, and said bridging contact member has its ends offset from the midportion in the same direction.

6. Contact structure for an electric switch as claimed in claim l wherein the cage comprises parallel side portions between said bridging Contact member is mountable by endwise insertion, and said bridging contact member has its ends offset from the midportion in the same direction, and stop means extending between said parallel sides limiting the movement of the contact member.

7. In an electric switch, fixed contact members each having contact surfaces on opposite sides thereof, fixed contact supporting means, a bridging contact adapted to bridge selectively a pair of said contact surfaces of said fixed contact members facing in one direction or a pair facing in the opposite direction, a movable contact carrier movable between two positions, a supporting cage for said bridging Contact secured on said carrier in which said bridging contact is mountable alternatively in spaced positions while said cage remains secured on said carrier, a movable means to bias the bridging contact from either end, alternatively, of the cage toward the opposite end depending in which of said spaced positions said bridging contact is mounted, means on said cage to limit the movement of said bridging contact by said biasing means, said bridging contact being normally engaged with said fixed contacts when biased toward one end of said cage and normally disengaged when biased to the other end of said cage.

8. In an electromagnetic switch, a mounting plate, an insulating member, fixed contacts mounted on said member, a movable carrier, movable contacts supported from and moved by said carrier, electromagnetic operating means including an armature connected with said carrier and movable between attracted and unattracted positions, means between said carrier and said mounting plate comprising a stud on one and a leaf spring on the other which are manually in position to hold said carrier in a neutral position between attracted and unattracted positions.

9. An electromagnetic switch as claimed in claim 8 in which said leaf spring and stud are normally disengaged and automatically returned to normally disengaged position on attraction of the armature after having been held in neutral position.

10. Contact structure as claimed in claim l having stop means on the cage limiting the action of the biasing means from one end of the cage toward said stop means.

ll. Contact structure as claimed in claim l0 wherein the cage has stop means limiting the movement of the contact member by said biasing means, said stop means also limiting the movement of momentarily-unemployed biasing means at the other end of the cage.

12. In an electric switch, fixed contact members having contact surfaces on opposite sides thereof, fixed Contact supporting means, a bridging contact adapted to bridge a pair of surfaces of said xed contact members, a movable contact carrier movable between two positions, a supporting cage for said bridging contact secured on said carrier in which said bridging Contact is mountable alternatively in spaced positions, biasing means adjacent each end of the cage to bias the bridging contact from either end, alternatively,` of the cage toward the opposite end depending in which of said spaced positions said bridging contact is mounted, means on said cage to limit the movement of the biasing means and to limit the movement of the bridging contact when engaged by a biasing means, said bridging contact being normally engaged with said fixed contacts when biased toward one end of 7 said cage and normally disengaged when biased to the othenendofsad cage.

13. Contact structure as claimed in claim 1 wherein theV biasing ymeansA comprises a spring pressed saddle member; and stop means on the cage limiting the move# ment of the saddle member and limiting the movement of the bridging contact when inserted between said saddle member and stop means.

2,276,698 Pierce Mar. 17, 1942 8 Schliecher Dec. 30, 1947 Hammerlyf.... Sept; 14, 1948'; Van-Valkenburg et a1,.. Mar; 11, 1952-l Taylor Apr. 24; 1956i Krenke et al. Y Sept; 18,'- 195.61 

